Coiled tubing system and method

ABSTRACT

Disclosed herein is a downhole coiled tubing system. The system includes, a bottom hole assembly, a coiled tubing string attached to the bottom hole assembly, and a conductor comprising an electrical signal carrier disposed within a control line, the conductor is disposed within the coiled tubing string and maintained substantially parallel with the coiled tubing string throughout the coiled tubing string and electrically coupled to the bottom hole assembly.

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority to U.S. provisional application, 61/029,033, filed Feb. 15, 2008, the entire contents of which are incorporated herein by reference.

BACKGROUND

In the hydrocarbon recovery industry, a clear desire has always been and always will be efficiency. Efficiency translates into greater profits for the well operator. Included in the repertoire for efficiency are downhole tools that benefit from power and signal from remote locations on a real time basis. Such has been provided in coiled tubing applications by running a wireline through the inside of a coiled tubing string. While this works for some applications, it suffers from disadvantages that in some cases are merely repressive of well activity and in other cases are preventative. One example of a downhole operation that is prevented by the use of a wireline in a coiled tubing is the mechanical setting of a completion using a tripping ball. This is because a tripping ball is likely to be impeded in reaching its intended destination by the wireline itself. The impedance is due to the girth of the wireline relative to the total inside dimensional area of the tubing string and or birdcaging of the wireline. Commonly, in order to remedy this situation, a coiled tubing run for drilling purposes is made using a wireline therein and then a coiled tubing conveyed completion run is made using coiled tubing without the wireline so that a tripping ball may be reliably dropped. While the method is effective it lacks efficiency.

BRIEF DESCRIPTION

Disclosed herein is a downhole coiled tubing system. The system includes, a bottom hole assembly, a coiled tubing string attached to the bottom hole assembly, and a conductor comprising an electrical signal carrier disposed within a control line, the conductor is disposed within the coiled tubing string and maintained substantially parallel with the coiled tubing string throughout the coiled tubing string and electrically coupled to the bottom hole assembly.

Further disclosed herein is a method of carrying out operations in a wellbore. The method includes, running a downhole coiled tubing system into the wellbore, maintaining the conductor substantially parallel to the coiled tubing string throughout the coiled tubing string, powering the bottom hole assembly with the conductor, and running well equipment through the coiled tubing string. The coiled tubing system includes, a bottom hole assembly, a coiled tubing string attached to the bottom hole assembly, and a conductor with an electrical signal carrier disposed within a control line, the conductor is disposed within the coiled tubing string and electrically coupled to the bottom hole assembly.

Further disclosed herein is a downhole coiled tubing system. The system includes, a coiled tubing string, a bottom hole assembly in operable communication with the coiled tubing, and a control line located within the coiled tubing string in operable communication with the bottom hole assembly and configured to elongate and contract substantially in unison with the coiled tubing string to avoid slacking of the control line within the coiled tubing string.

BRIEF DESCRIPTION OF THE DRAWINGS

Referring now to the drawings wherein like elements are numbered alike in the several Figures:

FIG. 1 is a schematic depiction of the newly disclosed coiled tubing conveyed bottom hole assembly with a signal conductor therein; and

FIG. 2 is a schematic representation of a conductor as taught herein.

DETAILED DESCRIPTION

It is common with existing systems to provide wireline slack in an amount approximating an anticipated amount of stretch that a coiled tubing will experience during use. This is because the wireline does not have similar stretch characteristics to the coiled tubing. Thus, if wireline slack is not pumped into the coiled tubing, the wireline is likely to become disengaged from a bottom hole assembly (BHA), break or both. Common usage then is to pump excess wireline into the coiled tubing. This requires work at the surface to pump the slack, machinery wear and tear, and time. The wireline slack is to be evenly distributed inside the coiled tubing to maintain the coupling with the BHA intact. Further, if wireline slack migrates to a particular area in the string, i.e. it is not distributed along the string; it can cause the outer armors of the wireline to “birdcage”. This is detrimental both because it prevents passage of other tools through the coiled tubing and because it can cause the wireline, therebelow, to become taught to the BHA, undermining the point of the slack in the first place. This condition necessitates a common art practice of back pumping the wireline over time to redistribute the same, thereby avoiding birdcaging. This operation is commonly known as “slack management”. The back pumping operation requires time and an interruption in normal circulation that slows the overall process being carried out in the wellbore. In addition, the sheer size of typical wireline is an impediment to running other tools through the tubing.

Referring to FIG. 1, a schematic illustration depicts the condition of a section of a coiled tubing string 112 and signal conductor 110 in accordance with the teaching hereof. In FIG. 1, it will be appreciated that the signal conductor 110 is significantly smaller in outside dimensions than an inner dimension of the coiled tubing 112. In one iteration, the conductor 110 is 3/16 inch in diameter. This leaves more of the inside dimension area of the coiled tubing string 112 available for other purposes including running other tools therethrough. For example, a coiled tubing configured as taught herein is employable for running and cementing liners and for subsequent disconnect of liners, among other things. These processes can be accomplished, for example, with tripping balls dropped from the surface, etc. Moreover, it will immediately be appreciated that the signal conductor 110 is positioned substantially in parallel with the coiled tubing 112. The signal conductor 110 has an elongation factor of about 45 percent, which factor is to be at least as great as an elongation factor of the coiled tubing string 112 in which the signal conductor 110 is intended to be disposed. This facilitates the parallel condition of the signal conductor 110 throughout the length of the coiled tubing string 112. Slack is not needed in the configuration as taught and consequently, slack management is not needed. One of ordinary skill in the art having read the foregoing paragraph will quickly realize that the configuration taught herein thus avoids wear and tear on injecting machines, reduces time of installation, substantially eliminates “birdcaging” and thereby improves the function of coiled tubing conveyed bottom hole assemblies. Because “birdcaging” does not form, there is no need to engage in the prior art required back pumping of the wireline.

Both the size of the conductor and the lack of slack facilitate the ability to run other tools through the coiled tubing string 112. Such tools include tripping balls and other devices for completion operations. The ability to run such other tools also means that drilling and completion can be accomplished using a single coiled tubing rather than in at least two as has typically been done heretofore.

Referring to FIG. 2, the signal conductor 110 comprises an electrical signal carrier 120 loosely disposed within a control line 130, the control line 130 comprising, in one embodiment, Incoloy® (nickel-chromium alloy) material. The signal carrier 120 is composed of a material capable of carrying either or both of power and data between a remote location and the BHA 114, such as a copper wire, for example. This allows for the BHA 114 to be powered by the signal conductor 110 and send data between the remote location such as the surface and itself while facilitating the benefits set forth above. In addition, the loose disposition of the signal carrier 120 within the control line 130 allows for pressure transmission as well as signal transmission. Pressure actuated features of the BHA 114 are also enabled using the signal conductor 110.

While preferred embodiments have been shown and described, modifications and substitutions may be made thereto without departing from the spirit and scope of the invention. Accordingly, it is to be understood that the present invention has been described by way of illustrations and not limitation. 

1. A downhole coiled tubing system comprising: a bottom hole assembly; a coiled tubing string attached to the bottom hole assembly; and a conductor comprising an electrical signal carrier disposed within a control line, the conductor being disposed within the coiled tubing string and maintained substantially parallel with the coiled tubing string throughout the coiled tubing string and electrically coupled to the bottom hole assembly.
 2. The downhole coiled tubing system as claimed in claim 1 wherein the bottom hole assembly includes mechanical actuatable components.
 3. The downhole coiled tubing system as claimed in claim 1 wherein the bottom hole assembly includes completion equipment.
 4. The downhole coiled tubing system as claimed in claim 3 wherein the completion equipment includes cementing equipment.
 5. The downhole coiled tubing system as claimed in claim 4 wherein the completion equipment includes liner release equipment.
 6. The downhole coiled tubing system as claimed in claim 1 wherein the conductor transmits power to the bottom hole assembly.
 7. The downhole coiled tubing system as claimed in claim 1 wherein the conductor transmits data therethrough between the bottom hole assembly and a remote location.
 8. The downhole coiled tubing system as claimed in claim 1 wherein the conductor further conveys fluid pressure.
 9. The downhole coiled tubing system as claimed in claim 1 wherein the conductor is loosely disposed within the coiled tubing string but without slack in the conductor.
 10. The downhole coiled tubing system as claimed in claim 1 wherein the conductor has an elongation factor of about 45 percent.
 11. The downhole coiled tubing system as claimed in claim 1 wherein the conductor has an elongation factor at least as great as that of the coiled tubing string.
 12. The downhole coiled tubing system as claimed in claim 1 wherein the downhole coiled tubing system remains in use sufficiently patent to pass other well equipment through the coiled tubing string.
 13. The downhole coiled tubing system as claimed in claim 12 wherein the other well equipment includes a tripping ball.
 14. The downhole coiled tubing system as claimed in claim 1 wherein the electrical signal carrier is a copper wire.
 15. The downhole coiled tubing system as claimed in claim 1 wherein the control line comprises nickel-chromium alloy.
 16. The downhole coiled tubing system as claimed in claim 1 wherein the electrical signal carrier is loosely disposed within the control line.
 17. A method of carrying out operations in a wellbore comprising: running a downhole coiled tubing system comprising: a bottom hole assembly; a coiled tubing string attached to the bottom hole assembly; and a conductor comprising an electrical signal carrier disposed within a control line, the conductor being disposed within the coiled tubing string and electrically coupled to the bottom hole assembly, into the wellbore; maintaining the conductor substantially parallel to the coiled tubing string throughout the coiled tubing string; powering the bottom hole assembly with the conductor; and running well equipment through the coiled tubing string.
 18. The method as claimed in claim 17 further comprising communicating data between a remote location and the bottom hole assembly along the conductor.
 19. The method as claimed in claim 17 wherein the running well equipment includes running a tripping ball.
 20. A downhole coiled tubing system, comprising: a coiled tubing string; a bottom hole assembly in operable communication with the coiled tubing; and a control line located within the coiled tubing string in operable communication with the bottom hole assembly and configured to elongate and contract substantially in unison with the coiled tubing string to avoid slacking of the control line within the coiled tubing string. 